Help with a function error.

[jmcorpse]

Hello,

I have been working on this program for the past four hours and was doing good till I got to this point. I am pretty sure that I probably can't do it this way, but I'm just learning and it isn't becoming apparent to me how to correct it. Any help would be appreciated. I apologize in advance if the code wrap did not work properly.

#include<iostream>
#include<cmath>


//Global Variables and Function declarations

double bmr(double P);//BMR = Basal Metabolic rate. This function declaration is for the first function.
double pa(double intensity, double P, double time);//PA = Physical Activity. This function declaration is for the second function.
double eda(double fav_food);//EDA = Energy to Digest food. This function declaration is for the third function.
double mcw(double cals_con, double bmr, double pa, double eda);//MCW = Maintaining current weight. This function declaration is for the fourth function.

int main()
{
    using namespace std;
    char rerun;
    
  do
  {
//This is the section where the variables will be declared for the program.    

    double P;//P = pounds
    double intensity;
    double time;
    double cals_con;
    double servings;
   

//This is the prompt area asking the user for the information needed to operate the program.
    cout << "\n\nPlease enter your weight: ";
    cin  >> P;
    cout << "\nPlease enter the estimated intensity between 1 and 20 of your activity: ";
    cin  >> intensity; 
    cout << "\nPlease enter the amount of time (in minutes) spent doing your activity: ";
    cin  >> time;
    cout << "\nPlease enter the amount of calories from your favorite food: ";
    cin  >> cals_con;
    cout << "\nPlease enter the number of servings of your favorite food: ";
    cin  >> servings;
      
//These are the statements giving the user the requested information.

    cout << "\nThe calories required for basic Basal Metobolic Rate is: " << bmr(P) << "." << endl;
    cout << "\nThe calories required for physical activity are: " << pa(intensity, P, time) << "." << endl;
    cout << "\nThe calories required for digestion are: " << eda(cals_con) << "."<< endl;
    cout << "\nThe calories required for maintaining body weight: " << mcw(cals_con, pa, bmr, eda) <<  "." << endl;
  
    cout << "\n Press 'y' if you would like to rerun this program.";
    cin  >> rerun;
  
  
   }
   while (rerun == 'Y' || rerun == 'y');
   return 0;
}

//This is the beginning of the function definitions.

   double bmr(double P)//Function definition one.
   {
       double bmr;
       double mid = (P/2.2);//This algorithm is dividing the pounds by 2.2 before moving on to raise it to the power of 0.756.
       bmr = 70 * pow(mid, 0.756);//This is the finished algorithm that produces the basal metabolic rate.
       
       return bmr;
   }
   double pa(double intensity, double P, double time)//Function definition two.
   {
       double pa;
       pa = 0.0385 * intensity * P * time;//This algorithm is used to calculate the calories needed for physical activity. 
       
       return pa;
   } 
   double eda(double cals_con)//Function definition three.
   {
       double eda;
       eda = cals_con * 0.1;//This algorithm is used to calculate the calories needed for digestion.
       
       return eda;
   }    
   double mcw(double cals_con, double pa, double bmr, double eda)//This algorithm is used to calculate the calories needed to maintain a body.
   {
       double mcw;
       double servings;
       
       double mid2 = bmr + pa + cals_con + eda;
       mcw = (mid2/servings);
       
       return mcw;
   }

The errors given are:
In function 'int main()':
Line 46: error: cannot convert 'double (*)(double, double, double)' to 'double' for argument '2' to 'double mcw(double, double, double, double)'
compilation terminated due to -Wfatal-errors.

[sundip]

In the line 46 you are using

mcw(cals_con, pa, bmr, eda)

you are passing pointer to function in place of double value(pa,bmr,eda).
Use

mcw(cals_con, pa(intensity, P, time), bmr(P), eda(cals_con))

in place of

mcw(cals_con, pa, bmr, eda)

.
It is always a good idea for beginners to use local variable to store the values of function return, and pass that variable to other function.

double pa_val  = pa(intensity, P, time);
double bmr_val = bmr(P);
double eda_val = eda(cals_con));

and call function with passing local variables

mcw(cals_con, pa_val, bmr_val, eda_val)

[jmcorpse]

Thanks for your help, it's making sense to me now.